Long-term obesity was associated with adulthood expression of biomarkers denoting antagonistic and integrative aging hallmarks, including mean (SD) hs-CRP (1.69 [2.1] vs 3.67 vs 4.24 [2.4] mg/L; P < .001; f = 0.57 [95% CI, 0.44-0.70]) and IL-6 (log, 0.69 [0.5] vs 1.03 [0.4] vs 0.99 [0.4]; P < .001; f = 0.53 [95% CI, 0.41-0.62]), as well as FGF-21, IGF-1, IGF-2, apelin, and irisin. This evidence concerns the gene IGF2 and obesity due to melanocortin 4 receptor deficiency.